Deck 6: Theory of Gas and Combustion

Question 1

Why is "inches of water column" used to measure gas pressure instead of psig?

Answer 1

"Inches of water column" is a smaller scale and will give more accurate measurements.

Question 2

The proper color of a gas flame is ____.

A) sharp all blue
B) lazy all blue
C) blue with slight orange tips
D) lazy with yellow tips

Answer 2

C

Question 3

The flame in a gas fired furnace is burning with heavy yellow tips. What is the problem?

Answer 3

There is not enough primary air. Check the air shutter opening and for debris in the furnace.

Question 4

Liquified petroleum (LP) is heavier than air and can cause suffocation if not handled properly.

Question 5

In the USA, natural gas suppliers supply gas with a heat content of about 1,050 Btu/cu. ft.

Question 6

The dangerous by-product of poor combustion of gas is ______________________________.

Question 7

If flue gases are not vented properly, carbon monoxide poisoning could result.

Question 8

The heat content of one gallon of No. 2 fuel oil is _________________________.

Question 9

A gas flame will carry electrical energy.

Question 10

What is the difference between a yellow gas flame and an orange gas flame?

Question 11

Three products of complete combustion of natural and LP gas are _________________________, ________________________, and _________________________.

Question 12

20 cubic feet of propane will produce how many Btu of heat?

A) 2,500
B) 50,000
C) 25000
D) 500,000

Question 13

Why do propane and butane gas furnaces require 100% shut off in the event of pilot outage?

Question 14

In a conventional gas furnace, the hot flue gases are ____.

A) forced out a PVC vent with a blower
B) recycled through a secondary heat exchanger and then vented through a draft diverter
C) forced through a type B vent by a blower
D) vented by natural convection